In recent years, consumers have been provided with a variety of devices and systems to enable them to locate places on a digital map using GPS (Global Positioning System) signal reception, processing functionality and/or gyroscope values within the devices and systems. The variety of devices and systems used by consumers are in the form of in-vehicle navigation systems that enable drivers to navigate over streets and roads; hand-held devices such as personal digital assistants (“PDAs”), personal navigation devices (PNDs), and cell phones or other types of mobile devices that can do the same; desktop applications, and Internet applications in which users can generate maps showing desired places. The common aspect in all of these and other types of devices and systems is a map database of geographic features, vectors and attributes, and software to access, manipulate and navigate the map database in response to user inputs.
Generally, localization in bifurcations is difficult for positioning and map matching systems. Small errors in gyroscope measurements and/or tiny miscalibrations cause heading errors that are large enough to result in a wrong location and direction being displayed on a navigation device. In such a case, the position and heading errors are in the range of map incertitudes with a risk for a mismatch. Detecting a bifurcation in such circumstances can help the localization process.